This study seeks to determine the safety, biological activity, and effect of SCH 58500 in the local-regional gene therapy of primary and metastatic malignant tumors of the liver which suffer p53 alteration. The study design consists of an open-label, nonrandomized, single-dose, dose-escalation Phase I trial. SCH 58500 will be administered by hepatic artery infusion to patients with primary (hepatocellular cancer) or metastatic (colorectal cancer) tumors of the liver.